Extech 445815 humidity alert ii hygro thermometer extech 445815 p damage resulting from high humidity and poor ventilation in storage rooms offices and houses not only costs money to repair but is also unhealthy and unsightly most people think that the dampness comes from outside but that is often not true in reality moisture is caused inside the house by evaporation in the kitchen and bathroom the use of highly insulating building materials greatly reduces ventilation which means th